Infinity is too much. How do scientists 'know' that space does not end?

Barrow boy

If I have understood your question correctly, you appear to be asserting that scientists claim that the universe is infinite. Nothing could be further from the truth. We live in a universe which may be vast, but nevertheless has a finite size. We cannot see or venture outside the universe (even if anything else exists) because it is a closed system. The universe has been expanding since the Big Bang and the question which has long intrigued scientists is whether the universe will implode back to a dot through gravitational forces, or whether it will continue to expand. On balance they now believe it will expand forever. Thought: so although the universe is finite, is time infinite? Jul 12 02, 8:28 PM

Gnomon

Scientists are yet undecided as to whether the universe is finite or infinite. They will decide this based on mathematical theories about how a universe should behave, based on observations of the part of the universe close to us. There is a basic assumption that the laws of nature that we see around us are the same throughout the universe. If so, then we can predict that if there is more than a certain amount of matter in the universe, its gravity will cause it to wrap around into a closed and finite system. If there is less than the critical amount, the universe will not bend around into a closed system, but will be infinite and unbounded. So we have the paradoxical situation that if there is less than a certain amount of matter in the universe, it is infinite, while if there is more than the critical limit, it is finite. Measurements of the matter density in the universe at present tend to suggest an infinite universe, but it is early days yet. Jul 12 02, 9:03 PM

Barrow boy

Gnomon, I see where you're coming from. Whatever the matter density of the universe it is still finite under existing understanding of laws of physics. When you quote an 'infinite universe' you surely mean that there is an infinite potential for expansion, ie infinite time. This causes the finite universe to expand forever making it infinite within the infinite time system. We're talking the same language in essence. When I was at school many years ago I had a brilliant physics teacher who wrote textbooks on modern physics, and I remember that he asserted that time was not a constant; the time we experience now was not a constant for eternity. There was a constant of 't-time' and 'tau-time'. Maybe, the universe will not be infinite because time will not be infinite. Sorry, Jane. You have unleashed a real forum discussion here. Jul 12 02, 9:41 PM

Brainy Blonde

This is right up there with time travel, and the Theory of Relativity! Many people, like myself, find it difficult to wrap their brain around these kinds of things. It makes my head spin like Linda Blair's!!!! I keep the pea soup to myself though!! LOL!!! A few weeks ago, while looking for something else, I came across Stephen Hawkings web site. Fascinating reading, but even he doesn't have an answer to this, just his own theories. Mind you, they are based on information and scientific laws that fly way over my head!!! Anyway, the following site has some very interesting information. http://www.pbs.org/wnet/hawking/html/home.html Hawking's own site is at: http://www.hawking.org.uk/ Jul 15 02, 12:48 AM